DESCRIPTION: The Mayak PA Workers' Early Clinical Effects (MWECE) Database is a longitudinal source of occupational exposure and health outcome data on a cohort of 591 Russian workers who began employment at the first Russian nuclear facility between the years 1948-1958. These data are uniquely significant because the workers received sustained occupational exposures of 1-10 Gy per year and 39% of the workers are women. The database is the product of 8 years of collaboration between Russian and US scientists and is located at the University of Pittsburgh. It includes more [unreadable] than 17,500 person years of longitudinal follow-up data and over 3.5 million data points. Missing data do not exceed 3% of the clinical data and 7% of the exposure data. The proposed work in the current application includes: (1) the transfer from Russia to the US of the most up-to-date dosimetry available on all 591 workers in the MWECE Database; (2) the inclusion of unique new medical outcome data into the database (i.e., detailed female reproductive histories; information on radiation burns, as well as data on occupational and lifestyle factors); and (3) completion of standard QA/QC procedures to insure the consistency and reliability of the new medical and dosimetric information in [unreadable] the database. We propose to use these new data to carry out priority clinical and epidemiological (dose-response) investigations of plutonium pneumosclerosis, negative reproductive events in females, and the effects of prior occupational radiation exposure on the clinical outcome of subsequent acute accident exposures. In addition, we propose to establish the scientific and administrative basis for opening up the information in the MWECE Database for research purposes to scientists who are not resident at the University of Pittsburgh. This last objective requires: (1) writing detailed descriptions of retrospective dose assessment procedures; (2) updating operational nomenclature and data description manuals; and (3) the completion of the introductory epidemiological and dosimetric analyses necessary to orient outside investigators to the content and limitations of the information available in the MWECE database. [unreadable] [unreadable]